Smoke Barrage via Smokey Shots

[Snarks]

Suggest adding a "Smoke Barrage" ability on the 105 Sherman with the unlock of Smokey Shots. This allows the unit an alternative utility function that players may pair up with other units to exploit, and allows for more flexibility in Armor Doctrine.

Smoke Barrage should have a lower cooldown but using the ability affects both barrage types, as with Mortar Barrage/Smoke.